A conventional manually operative steering system of an outboard motor exhibits a problem of increased steering load, which may result in difficulty of the steering operation, in accordance with wind and wave conditions, the speed of the hull, the navigation conditions of the hull, the trim angle of the outboard motor and like conditions.
In order to obviate the problems encountered with the conventional manual steering system, a hydraulic power steering system has also been proposed.
The proposed hydraulic power steering system is generally composed of the manual power steering system with which a power unit is associated. In such a hydraulic power steering system, the power unit is equipped with a hydraulic pump for generating a steering assist force.
However, the hydraulic power steering system of the prior art utilizes a power source of the outboard motor itself as the power source for driving a hydraulic pump. Accordingly, the hydraulic power steering system itself is complicated in structure and, moreover, in the case where it is required to apply the hydraulic power steering system to an existing outboard motor, the drive shaft within the drive shaft housing may be changed, such being troublesome and uneconomical.